Meaning: 1. The wearing away of exterior or peripheral material by melting, friction, or burning, as the ablation of a glacier by melting or scraping against rock or the ablation of a burning meteorite streaking across the sky. 2. The surgical removal of a body part by excision or amputation.

Notes:Ablation sounds very much like two other words, oblation "an offering to a deity" and ablution "ritual washing in a religious ceremony"; be careful not to confuse them. Today's word, of course, is the action noun of the verb ablate "to remove or wear away". The adjective, ablative [æb-lê-tive] now only refers to the inflectional case, an ending added to nouns giving them the meaning "away from". For example, the Turkish ablative suffix -den converts otel "hotel" into otelden "from the hotel".

In Play: Today's Good Word most often turns up in the halls of science: "As a rocket's nose cone reenters the Earth's atmosphere, it heats to the point that outer layers are lost to ablation." In fact, later nose cones were covered with an ablator, a layer applied just to be burned away during descent. Rock, dirt, and other materials worn away from the land by the ablation of glaciers, pile up in mounds called moraines. "Felix lived on a moraine built up from the ablation of a glacier during the last ice age."

Word History: Today's Good Word comes from Latin ablatio(n) "carrying away" from ablatus, the past participle of auferre "to carry away", based on ab "away" and ferre "take, carry". Ab comes from the same earlier stem as English off and of. The past participle of the Latin word ferre "to take, carry" is the odd ball latus "taken, carried", which was originally (to)l-at-us, with the participle suffix -at (related to the English participle suffix -ed) plus the masculine gender ending -us. So the original stem was tol-, the root of tolerare "to bear, put up with", from which English borrowed tolerate. (Before we get carried away with today's etymology, let's thank Dr. Margie Swed for suggesting today's Good Word.)